On Sun, 2009-05-31 at 08:52 -0500, flint wrote:
> sent this before, don't know if it went through... someone please reply if
> it went, even if they don't know answer?...
>
> so here's the scenario..
>
> I have a site that uses php with a database to offer sound files to
> users using streaming methods.
>
> the request page has options, allowing the user to modify the sound
> file in various ways, before having it sent to them
>
> Here's the problem:
>
> The method i'm using to feed the data to the user is to run the source
> file through various piped commands, with the resulting audio being
> dumped to stdout, and then using passthru in php to get that data to
> the enduser.
>
> here's an example, for serving an MP3 with its pitch/speed changed by sox:
>
> passthru("lame --quiet --decode \"" . $in_file . "\" - | " .
> "sox -V -S -t wav - -t wav - speed " . $speed_factor . " | " .
> "lame --quiet " . $lame_params . " - -");
>
> This works just fine, except the problem is if the end user aborts the
> transfer (e.g. stops playback in the media player, cancels download of
> the mp3, whatever) then it leaves behind both the sox process and the
> decoder LAMe process along with the sh that's running them. the only
> process that exits is the final encoding lame process. If the sound
> file runs to completion, everythign exits properly.
>
> But this obviously means enough "cancelling" of downloads means the
> server ends up with a huge batch of stuck processes! And I even tried
> simply killing the 'host' sh process, and the lame and sox processes
> remain anyway. The only way I've been able to deal with this is
> manually killing the lame and sox processes directly.
>
> is there any way I can make this work, such so that if the user
> cancels the transfer, all relavent processes are killed rather than
> just the single process that's feeding output into php?
Use something else to pass the data back to the user... popen() comes to
mind or proc_open(). Then disable auto abort on user disconnect via
ignore_user_abort(). Then after sending periodic data chunks, check the
user connection status via connection_aborted(). If your script finds
that the user has aborted, then kill all the processes in the pipeline
from the PHP script before finally aborting the PHP script itself.
Cheers,
Rob.
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http://www.interjinn.com
Application and Templating Framework for PHP
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